<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <div>b页面 </div>
  <div id="session"></div>
  <a href="http://localhost:5000/b"> 5000 b 页面</a>
  <script>
    let session = sessionStorage.getItem("session", 1234)
    document.querySelector('#session').innerHTML = session;
  </script>
</body>

</html>